The invention relates to a matrix type recording/reading head for information media in which the elementary heads are arranged in the form of a zigzag structure. It can be applied especially to the recording/reading of multitrack recording media such as magnetic recorder tapes in the technologies of computer peripherals, professional recorders, professional video tape recorders as well as video tape recorders used for large scale consumer applications.
Matrix head structures designed for multitrack recording on magnetic tapes have been described in the French patent No. 2 630 853. As can be seen in FIGS. 1 to 3, the head consists of two functional sub-assemblies: an upper part, made in the form of thin layers having the gaps M1, M2 and the magnetic poles of the heads 17.1, 18.1, and a lower part generally made by means of conventional technology (in volume) bearing the excitation coils (14.1). The invention relates to an arrangement of the magnetic poles and of the gaps by which the working of the component can be made less sensitive to the imperfections of guidance of the magnetic tape.
The device includes a wafer 10 made of magnetic material such as ferrite with rectilinear grooves 11.sub.1, 11.sub.2 . . . , 12.sub.1, 12.sub.2 . . . on one of its faces 13. The grooves 11.sub.1, 11.sub.2 . . . are parallel to each other and form rows while the grooves 12.sub.1, 12.sub.2 . . . are perpendicular to the rows and form columns. In each groove, there is an electrical conductor 14.sub.1, 14.sub.2 . . . , 15.sub.1, 15.sub.2 . . . The conductor 14.sub.1 is placed in the groove 11.sub.1, the conductor 14.sub.2 is placed in groove 11.sub.2, . . . , the conductor 15.sub.1 is in groove 12.sub.1 etc. Another wafer 16 is bonded to the wafer 10. The wafer 16 is made of nonmagnetic material. On the unoccupied face 16.sub.1 of the wafer 16 are formed the pole pieces 17, 18 and the gap 19 of a series of magnetic heads, the number of which is equal to the number of intersections.
In order to make devices enabling the recording of the narrow contiguous tracks without placing excessive constraints on the technology, all the writing gaps are arranged in n columns of m gaps (FIG. 1). These various gaps are offset with respect to one another in order to fill the surface of the tape with contiguous tracks (FIG. 2). The gaps are therefore positioned in an oblique network whose horizontal and vertical periods are substantially greater than the track width. This arrangement leads to writing that is spatially offset on each of the tracks. If the tape is affected by guiding defects leading to vertical shifts, the heads located towards the rear may partially erase the tracks already written on by the heads located in the front (FIG. 3). The most critical case is that of the last column of the heads facing the tracks written on by the first column, since the spatial distance between these two groups of tracks is n times greater than it is between the other consecutive groups of tracks. Owing to this effect, it becomes necessary to compress the dynamic constraints of guidance by a factor n, or not to use the first group of tracks to its maximum capacity.
The means of avoiding this effect is to position the gaps in such a way that the contiguous tracks are always written on by groups of gaps whose distance in the running direction is the minimum, namely by neighboring groups of gaps (or possibly by the same group of gaps).